// cuon-matrix.js (c) 2012 kanda and matsuda
/**
 * This is a class treating 4x4 matrix.
 * This class contains the function that is equivalent to OpenGL matrix stack.
 * The matrix after conversion is calculated by multiplying a conversion matrix from the right.
 * The matrix is replaced by the calculated result.
 */

/**
 * Constructor of Matrix4
 * If opt_src is specified, new matrix is initialized by opt_src.
 * Otherwise, new matrix is initialized by identity matrix.
 * @param opt_src source matrix(option)
 */
var Matrix4 = function (opt_src) {
  var i, s, d;
  if (opt_src && typeof opt_src === 'object' && opt_src.hasOwnProperty('elements')) {
    s = opt_src.elements;
    d = new Float32Array(16);
    for (i = 0; i < 16; ++i) {
      d[i] = s[i];
    }
    this.elements = d;
  } else {
    this.elements = new Float32Array([1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]);
  }
};

/**
 * Set the identity matrix.
 * @return this
 */
Matrix4.prototype.setIdentity = function () {
  var e = this.elements;
  e[0] = 1; e[4] = 0; e[8] = 0; e[12] = 0;
  e[1] = 0; e[5] = 1; e[9] = 0; e[13] = 0;
  e[2] = 0; e[6] = 0; e[10] = 1; e[14] = 0;
  e[3] = 0; e[7] = 0; e[11] = 0; e[15] = 1;
  return this;
};

/**
 * Copy matrix.
 * @param src source matrix
 * @return this
 */
Matrix4.prototype.set = function (src) {
  var i, s, d;

  s = src.elements;
  d = this.elements;

  if (s === d) {
    return;
  }

  for (i = 0; i < 16; ++i) {
    d[i] = s[i];
  }

  return this;
};

/**
 * Multiply the matrix from the right.
 * @param other The multiply matrix
 * @return this
 */
Matrix4.prototype.concat = function (other) {
  var i, e, a, b, ai0, ai1, ai2, ai3;

  // Calculate e = a * b
  e = this.elements;
  a = this.elements;
  b = other.elements;

  // If e equals b, copy b to temporary matrix.
  if (e === b) {
    b = new Float32Array(16);
    for (i = 0; i < 16; ++i) {
      b[i] = e[i];
    }
  }

  for (i = 0; i < 4; i++) {
    ai0 = a[i]; ai1 = a[i + 4]; ai2 = a[i + 8]; ai3 = a[i + 12];
    e[i] = ai0 * b[0] + ai1 * b[1] + ai2 * b[2] + ai3 * b[3];
    e[i + 4] = ai0 * b[4] + ai1 * b[5] + ai2 * b[6] + ai3 * b[7];
    e[i + 8] = ai0 * b[8] + ai1 * b[9] + ai2 * b[10] + ai3 * b[11];
    e[i + 12] = ai0 * b[12] + ai1 * b[13] + ai2 * b[14] + ai3 * b[15];
  }

  return this;
};
Matrix4.prototype.multiply = Matrix4.prototype.concat;

/**
 * Multiply the three-dimensional vector.
 * @param pos  The multiply vector
 * @return The result of multiplication(Float32Array)
 */
Matrix4.prototype.multiplyVector3 = function (pos) {
  var e = this.elements;
  var p = pos.elements;
  var v = new Vector3();
  var result = v.elements;

  result[0] = p[0] * e[0] + p[1] * e[4] + p[2] * e[8] + e[11];
  result[1] = p[0] * e[1] + p[1] * e[5] + p[2] * e[9] + e[12];
  result[2] = p[0] * e[2] + p[1] * e[6] + p[2] * e[10] + e[13];

  return v;
};

/**
 * Multiply the four-dimensional vector.
 * @param pos  The multiply vector
 * @return The result of multiplication(Float32Array)
 */
Matrix4.prototype.multiplyVector4 = function (pos) {
  var e = this.elements;
  var p = pos.elements;
  var v = new Vector4();
  var result = v.elements;

  result[0] = p[0] * e[0] + p[1] * e[4] + p[2] * e[8] + p[3] * e[12];
  result[1] = p[0] * e[1] + p[1] * e[5] + p[2] * e[9] + p[3] * e[13];
  result[2] = p[0] * e[2] + p[1] * e[6] + p[2] * e[10] + p[3] * e[14];
  result[3] = p[0] * e[3] + p[1] * e[7] + p[2] * e[11] + p[3] * e[15];

  return v;
};

/**
 * Transpose the matrix.
 * @return this
 */
Matrix4.prototype.transpose = function () {
  var e, t;

  e = this.elements;

  t = e[1]; e[1] = e[4]; e[4] = t;
  t = e[2]; e[2] = e[8]; e[8] = t;
  t = e[3]; e[3] = e[12]; e[12] = t;
  t = e[6]; e[6] = e[9]; e[9] = t;
  t = e[7]; e[7] = e[13]; e[13] = t;
  t = e[11]; e[11] = e[14]; e[14] = t;

  return this;
};

/**
 * Calculate the inverse matrix of specified matrix, and set to this.
 * @param other The source matrix
 * @return this
 */
Matrix4.prototype.setInverseOf = function (other) {
  var i, s, d, inv, det;

  s = other.elements;
  d = this.elements;
  inv = new Float32Array(16);

  inv[0] = s[5] * s[10] * s[15] - s[5] * s[11] * s[14] - s[9] * s[6] * s[15]
    + s[9] * s[7] * s[14] + s[13] * s[6] * s[11] - s[13] * s[7] * s[10];
  inv[4] = - s[4] * s[10] * s[15] + s[4] * s[11] * s[14] + s[8] * s[6] * s[15]
    - s[8] * s[7] * s[14] - s[12] * s[6] * s[11] + s[12] * s[7] * s[10];
  inv[8] = s[4] * s[9] * s[15] - s[4] * s[11] * s[13] - s[8] * s[5] * s[15]
    + s[8] * s[7] * s[13] + s[12] * s[5] * s[11] - s[12] * s[7] * s[9];
  inv[12] = - s[4] * s[9] * s[14] + s[4] * s[10] * s[13] + s[8] * s[5] * s[14]
    - s[8] * s[6] * s[13] - s[12] * s[5] * s[10] + s[12] * s[6] * s[9];

  inv[1] = - s[1] * s[10] * s[15] + s[1] * s[11] * s[14] + s[9] * s[2] * s[15]
    - s[9] * s[3] * s[14] - s[13] * s[2] * s[11] + s[13] * s[3] * s[10];
  inv[5] = s[0] * s[10] * s[15] - s[0] * s[11] * s[14] - s[8] * s[2] * s[15]
    + s[8] * s[3] * s[14] + s[12] * s[2] * s[11] - s[12] * s[3] * s[10];
  inv[9] = - s[0] * s[9] * s[15] + s[0] * s[11] * s[13] + s[8] * s[1] * s[15]
    - s[8] * s[3] * s[13] - s[12] * s[1] * s[11] + s[12] * s[3] * s[9];
  inv[13] = s[0] * s[9] * s[14] - s[0] * s[10] * s[13] - s[8] * s[1] * s[14]
    + s[8] * s[2] * s[13] + s[12] * s[1] * s[10] - s[12] * s[2] * s[9];

  inv[2] = s[1] * s[6] * s[15] - s[1] * s[7] * s[14] - s[5] * s[2] * s[15]
    + s[5] * s[3] * s[14] + s[13] * s[2] * s[7] - s[13] * s[3] * s[6];
  inv[6] = - s[0] * s[6] * s[15] + s[0] * s[7] * s[14] + s[4] * s[2] * s[15]
    - s[4] * s[3] * s[14] - s[12] * s[2] * s[7] + s[12] * s[3] * s[6];
  inv[10] = s[0] * s[5] * s[15] - s[0] * s[7] * s[13] - s[4] * s[1] * s[15]
    + s[4] * s[3] * s[13] + s[12] * s[1] * s[7] - s[12] * s[3] * s[5];
  inv[14] = - s[0] * s[5] * s[14] + s[0] * s[6] * s[13] + s[4] * s[1] * s[14]
    - s[4] * s[2] * s[13] - s[12] * s[1] * s[6] + s[12] * s[2] * s[5];

  inv[3] = - s[1] * s[6] * s[11] + s[1] * s[7] * s[10] + s[5] * s[2] * s[11]
    - s[5] * s[3] * s[10] - s[9] * s[2] * s[7] + s[9] * s[3] * s[6];
  inv[7] = s[0] * s[6] * s[11] - s[0] * s[7] * s[10] - s[4] * s[2] * s[11]
    + s[4] * s[3] * s[10] + s[8] * s[2] * s[7] - s[8] * s[3] * s[6];
  inv[11] = - s[0] * s[5] * s[11] + s[0] * s[7] * s[9] + s[4] * s[1] * s[11]
    - s[4] * s[3] * s[9] - s[8] * s[1] * s[7] + s[8] * s[3] * s[5];
  inv[15] = s[0] * s[5] * s[10] - s[0] * s[6] * s[9] - s[4] * s[1] * s[10]
    + s[4] * s[2] * s[9] + s[8] * s[1] * s[6] - s[8] * s[2] * s[5];

  det = s[0] * inv[0] + s[1] * inv[4] + s[2] * inv[8] + s[3] * inv[12];
  if (det === 0) {
    return this;
  }

  det = 1 / det;
  for (i = 0; i < 16; i++) {
    d[i] = inv[i] * det;
  }

  return this;
};

/**
 * Calculate the inverse matrix of this, and set to this.
 * @return this
 */
Matrix4.prototype.invert = function () {
  return this.setInverseOf(this);
};

/**
 * Set the orthographic projection matrix.
 * @param left The coordinate of the left of clipping plane.
 * @param right The coordinate of the right of clipping plane.
 * @param bottom The coordinate of the bottom of clipping plane.
 * @param top The coordinate of the top top clipping plane.
 * @param near The distances to the nearer depth clipping plane. This value is minus if the plane is to be behind the viewer.
 * @param far The distances to the farther depth clipping plane. This value is minus if the plane is to be behind the viewer.
 * @return this
 */
Matrix4.prototype.setOrtho = function (left, right, bottom, top, near, far) {
  var e, rw, rh, rd;

  if (left === right || bottom === top || near === far) {
    throw 'null frustum';
  }

  rw = 1 / (right - left);
  rh = 1 / (top - bottom);
  rd = 1 / (far - near);

  e = this.elements;

  e[0] = 2 * rw;
  e[1] = 0;
  e[2] = 0;
  e[3] = 0;

  e[4] = 0;
  e[5] = 2 * rh;
  e[6] = 0;
  e[7] = 0;

  e[8] = 0;
  e[9] = 0;
  e[10] = -2 * rd;
  e[11] = 0;

  e[12] = -(right + left) * rw;
  e[13] = -(top + bottom) * rh;
  e[14] = -(far + near) * rd;
  e[15] = 1;

  return this;
};

/**
 * Multiply the orthographic projection matrix from the right.
 * @param left The coordinate of the left of clipping plane.
 * @param right The coordinate of the right of clipping plane.
 * @param bottom The coordinate of the bottom of clipping plane.
 * @param top The coordinate of the top top clipping plane.
 * @param near The distances to the nearer depth clipping plane. This value is minus if the plane is to be behind the viewer.
 * @param far The distances to the farther depth clipping plane. This value is minus if the plane is to be behind the viewer.
 * @return this
 */
Matrix4.prototype.ortho = function (left, right, bottom, top, near, far) {
  return this.concat(new Matrix4().setOrtho(left, right, bottom, top, near, far));
};

/**
 * Set the perspective projection matrix.
 * @param left The coordinate of the left of clipping plane.
 * @param right The coordinate of the right of clipping plane.
 * @param bottom The coordinate of the bottom of clipping plane.
 * @param top The coordinate of the top top clipping plane.
 * @param near The distances to the nearer depth clipping plane. This value must be plus value.
 * @param far The distances to the farther depth clipping plane. This value must be plus value.
 * @return this
 */
Matrix4.prototype.setFrustum = function (left, right, bottom, top, near, far) {
  var e, rw, rh, rd;

  if (left === right || top === bottom || near === far) {
    throw 'null frustum';
  }
  if (near <= 0) {
    throw 'near <= 0';
  }
  if (far <= 0) {
    throw 'far <= 0';
  }

  rw = 1 / (right - left);
  rh = 1 / (top - bottom);
  rd = 1 / (far - near);

  e = this.elements;

  e[0] = 2 * near * rw;
  e[1] = 0;
  e[2] = 0;
  e[3] = 0;

  e[4] = 0;
  e[5] = 2 * near * rh;
  e[6] = 0;
  e[7] = 0;

  e[8] = (right + left) * rw;
  e[9] = (top + bottom) * rh;
  e[10] = -(far + near) * rd;
  e[11] = -1;

  e[12] = 0;
  e[13] = 0;
  e[14] = -2 * near * far * rd;
  e[15] = 0;

  return this;
};

/**
 * Multiply the perspective projection matrix from the right.
 * @param left The coordinate of the left of clipping plane.
 * @param right The coordinate of the right of clipping plane.
 * @param bottom The coordinate of the bottom of clipping plane.
 * @param top The coordinate of the top top clipping plane.
 * @param near The distances to the nearer depth clipping plane. This value must be plus value.
 * @param far The distances to the farther depth clipping plane. This value must be plus value.
 * @return this
 */
Matrix4.prototype.frustum = function (left, right, bottom, top, near, far) {
  return this.concat(new Matrix4().setFrustum(left, right, bottom, top, near, far));
};

/**
 * Set the perspective projection matrix by fovy and aspect.
 * @param fovy The angle between the upper and lower sides of the frustum.
 * @param aspect The aspect ratio of the frustum. (width/height)
 * @param near The distances to the nearer depth clipping plane. This value must be plus value.
 * @param far The distances to the farther depth clipping plane. This value must be plus value.
 * @return this
 */
Matrix4.prototype.setPerspective = function (fovy, aspect, near, far) {
  var e, rd, s, ct;

  if (near === far || aspect === 0) {
    throw 'null frustum';
  }
  if (near <= 0) {
    throw 'near <= 0';
  }
  if (far <= 0) {
    throw 'far <= 0';
  }

  fovy = Math.PI * fovy / 180 / 2;
  s = Math.sin(fovy);
  if (s === 0) {
    throw 'null frustum';
  }

  rd = 1 / (far - near);
  ct = Math.cos(fovy) / s;

  e = this.elements;

  e[0] = ct / aspect;
  e[1] = 0;
  e[2] = 0;
  e[3] = 0;

  e[4] = 0;
  e[5] = ct;
  e[6] = 0;
  e[7] = 0;

  e[8] = 0;
  e[9] = 0;
  e[10] = -(far + near) * rd;
  e[11] = -1;

  e[12] = 0;
  e[13] = 0;
  e[14] = -2 * near * far * rd;
  e[15] = 0;

  return this;
};

/**
 * Multiply the perspective projection matrix from the right.
 * @param fovy The angle between the upper and lower sides of the frustum.
 * @param aspect The aspect ratio of the frustum. (width/height)
 * @param near The distances to the nearer depth clipping plane. This value must be plus value.
 * @param far The distances to the farther depth clipping plane. This value must be plus value.
 * @return this
 */
Matrix4.prototype.perspective = function (fovy, aspect, near, far) {
  return this.concat(new Matrix4().setPerspective(fovy, aspect, near, far));
};

/**
 * Set the matrix for scaling.
 * @param x The scale factor along the X axis
 * @param y The scale factor along the Y axis
 * @param z The scale factor along the Z axis
 * @return this
 */
Matrix4.prototype.setScale = function (x, y, z) {
  var e = this.elements;
  e[0] = x; e[4] = 0; e[8] = 0; e[12] = 0;
  e[1] = 0; e[5] = y; e[9] = 0; e[13] = 0;
  e[2] = 0; e[6] = 0; e[10] = z; e[14] = 0;
  e[3] = 0; e[7] = 0; e[11] = 0; e[15] = 1;
  return this;
};

/**
 * Multiply the matrix for scaling from the right.
 * @param x The scale factor along the X axis
 * @param y The scale factor along the Y axis
 * @param z The scale factor along the Z axis
 * @return this
 */
Matrix4.prototype.scale = function (x, y, z) {
  var e = this.elements;
  e[0] *= x; e[4] *= y; e[8] *= z;
  e[1] *= x; e[5] *= y; e[9] *= z;
  e[2] *= x; e[6] *= y; e[10] *= z;
  e[3] *= x; e[7] *= y; e[11] *= z;
  return this;
};

/**
 * Set the matrix for translation.
 * @param x The X value of a translation.
 * @param y The Y value of a translation.
 * @param z The Z value of a translation.
 * @return this
 */
Matrix4.prototype.setTranslate = function (x, y, z) {
  var e = this.elements;
  e[0] = 1; e[4] = 0; e[8] = 0; e[12] = x;
  e[1] = 0; e[5] = 1; e[9] = 0; e[13] = y;
  e[2] = 0; e[6] = 0; e[10] = 1; e[14] = z;
  e[3] = 0; e[7] = 0; e[11] = 0; e[15] = 1;
  return this;
};

/**
 * Multiply the matrix for translation from the right.
 * @param x The X value of a translation.
 * @param y The Y value of a translation.
 * @param z The Z value of a translation.
 * @return this
 */
Matrix4.prototype.translate = function (x, y, z) {
  var e = this.elements;
  e[12] += e[0] * x + e[4] * y + e[8] * z;
  e[13] += e[1] * x + e[5] * y + e[9] * z;
  e[14] += e[2] * x + e[6] * y + e[10] * z;
  e[15] += e[3] * x + e[7] * y + e[11] * z;
  return this;
};

/**
 * Set the matrix for rotation.
 * The vector of rotation axis may not be normalized.
 * @param angle The angle of rotation (degrees)
 * @param x The X coordinate of vector of rotation axis.
 * @param y The Y coordinate of vector of rotation axis.
 * @param z The Z coordinate of vector of rotation axis.
 * @return this
 */
Matrix4.prototype.setRotate = function (angle, x, y, z) {
  var e, s, c, len, rlen, nc, xy, yz, zx, xs, ys, zs;

  angle = Math.PI * angle / 180;
  e = this.elements;

  s = Math.sin(angle);
  c = Math.cos(angle);

  if (0 !== x && 0 === y && 0 === z) {
    // Rotation around X axis
    if (x < 0) {
      s = -s;
    }
    e[0] = 1; e[4] = 0; e[8] = 0; e[12] = 0;
    e[1] = 0; e[5] = c; e[9] = -s; e[13] = 0;
    e[2] = 0; e[6] = s; e[10] = c; e[14] = 0;
    e[3] = 0; e[7] = 0; e[11] = 0; e[15] = 1;
  } else if (0 === x && 0 !== y && 0 === z) {
    // Rotation around Y axis
    if (y < 0) {
      s = -s;
    }
    e[0] = c; e[4] = 0; e[8] = s; e[12] = 0;
    e[1] = 0; e[5] = 1; e[9] = 0; e[13] = 0;
    e[2] = -s; e[6] = 0; e[10] = c; e[14] = 0;
    e[3] = 0; e[7] = 0; e[11] = 0; e[15] = 1;
  } else if (0 === x && 0 === y && 0 !== z) {
    // Rotation around Z axis
    if (z < 0) {
      s = -s;
    }
    e[0] = c; e[4] = -s; e[8] = 0; e[12] = 0;
    e[1] = s; e[5] = c; e[9] = 0; e[13] = 0;
    e[2] = 0; e[6] = 0; e[10] = 1; e[14] = 0;
    e[3] = 0; e[7] = 0; e[11] = 0; e[15] = 1;
  } else {
    // Rotation around another axis
    len = Math.sqrt(x * x + y * y + z * z);
    if (len !== 1) {
      rlen = 1 / len;
      x *= rlen;
      y *= rlen;
      z *= rlen;
    }
    nc = 1 - c;
    xy = x * y;
    yz = y * z;
    zx = z * x;
    xs = x * s;
    ys = y * s;
    zs = z * s;

    e[0] = x * x * nc + c;
    e[1] = xy * nc + zs;
    e[2] = zx * nc - ys;
    e[3] = 0;

    e[4] = xy * nc - zs;
    e[5] = y * y * nc + c;
    e[6] = yz * nc + xs;
    e[7] = 0;

    e[8] = zx * nc + ys;
    e[9] = yz * nc - xs;
    e[10] = z * z * nc + c;
    e[11] = 0;

    e[12] = 0;
    e[13] = 0;
    e[14] = 0;
    e[15] = 1;
  }

  return this;
};

/**
 * Multiply the matrix for rotation from the right.
 * The vector of rotation axis may not be normalized.
 * @param angle The angle of rotation (degrees)
 * @param x The X coordinate of vector of rotation axis.
 * @param y The Y coordinate of vector of rotation axis.
 * @param z The Z coordinate of vector of rotation axis.
 * @return this
 */
Matrix4.prototype.rotate = function (angle, x, y, z) {
  return this.concat(new Matrix4().setRotate(angle, x, y, z));
};

/**
 * Set the viewing matrix.
 * @param eyeX, eyeY, eyeZ The position of the eye point.
 * @param centerX, centerY, centerZ The position of the reference point.
 * @param upX, upY, upZ The direction of the up vector.
 * @return this
 */
Matrix4.prototype.setLookAt = function (eyeX, eyeY, eyeZ, centerX, centerY, centerZ, upX, upY, upZ) {
  var e, fx, fy, fz, rlf, sx, sy, sz, rls, ux, uy, uz;

  fx = centerX - eyeX;
  fy = centerY - eyeY;
  fz = centerZ - eyeZ;

  // Normalize f.
  rlf = 1 / Math.sqrt(fx * fx + fy * fy + fz * fz);
  fx *= rlf;
  fy *= rlf;
  fz *= rlf;

  // Calculate cross product of f and up.
  sx = fy * upZ - fz * upY;
  sy = fz * upX - fx * upZ;
  sz = fx * upY - fy * upX;

  // Normalize s.
  rls = 1 / Math.sqrt(sx * sx + sy * sy + sz * sz);
  sx *= rls;
  sy *= rls;
  sz *= rls;

  // Calculate cross product of s and f.
  ux = sy * fz - sz * fy;
  uy = sz * fx - sx * fz;
  uz = sx * fy - sy * fx;

  // Set to this.
  e = this.elements;
  e[0] = sx;
  e[1] = ux;
  e[2] = -fx;
  e[3] = 0;

  e[4] = sy;
  e[5] = uy;
  e[6] = -fy;
  e[7] = 0;

  e[8] = sz;
  e[9] = uz;
  e[10] = -fz;
  e[11] = 0;

  e[12] = 0;
  e[13] = 0;
  e[14] = 0;
  e[15] = 1;

  // Translate.
  return this.translate(-eyeX, -eyeY, -eyeZ);
};

/**
 * Multiply the viewing matrix from the right.
 * @param eyeX, eyeY, eyeZ The position of the eye point.
 * @param centerX, centerY, centerZ The position of the reference point.
 * @param upX, upY, upZ The direction of the up vector.
 * @return this
 */
Matrix4.prototype.lookAt = function (eyeX, eyeY, eyeZ, centerX, centerY, centerZ, upX, upY, upZ) {
  return this.concat(new Matrix4().setLookAt(eyeX, eyeY, eyeZ, centerX, centerY, centerZ, upX, upY, upZ));
};

/**
 * Multiply the matrix for project vertex to plane from the right.
 * @param plane The array[A, B, C, D] of the equation of plane "Ax + By + Cz + D = 0".
 * @param light The array which stored coordinates of the light. if light[3]=0, treated as parallel light.
 * @return this
 */
Matrix4.prototype.dropShadow = function (plane, light) {
  var mat = new Matrix4();
  var e = mat.elements;

  var dot = plane[0] * light[0] + plane[1] * light[1] + plane[2] * light[2] + plane[3] * light[3];

  e[0] = dot - light[0] * plane[0];
  e[1] = - light[1] * plane[0];
  e[2] = - light[2] * plane[0];
  e[3] = - light[3] * plane[0];

  e[4] = - light[0] * plane[1];
  e[5] = dot - light[1] * plane[1];
  e[6] = - light[2] * plane[1];
  e[7] = - light[3] * plane[1];

  e[8] = - light[0] * plane[2];
  e[9] = - light[1] * plane[2];
  e[10] = dot - light[2] * plane[2];
  e[11] = - light[3] * plane[2];

  e[12] = - light[0] * plane[3];
  e[13] = - light[1] * plane[3];
  e[14] = - light[2] * plane[3];
  e[15] = dot - light[3] * plane[3];

  return this.concat(mat);
}

/**
 * Multiply the matrix for project vertex to plane from the right.(Projected by parallel light.)
 * @param normX, normY, normZ The normal vector of the plane.(Not necessary to be normalized.)
 * @param planeX, planeY, planeZ The coordinate of arbitrary points on a plane.
 * @param lightX, lightY, lightZ The vector of the direction of light.(Not necessary to be normalized.)
 * @return this
 */
Matrix4.prototype.dropShadowDirectionally = function (normX, normY, normZ, planeX, planeY, planeZ, lightX, lightY, lightZ) {
  var a = planeX * normX + planeY * normY + planeZ * normZ;
  return this.dropShadow([normX, normY, normZ, -a], [lightX, lightY, lightZ, 0]);
};

/**
 * Constructor of Vector3
 * If opt_src is specified, new vector is initialized by opt_src.
 * @param opt_src source vector(option)
 */
var Vector3 = function (opt_src) {
  var v = new Float32Array(3);
  if (opt_src && typeof opt_src === 'object') {
    v[0] = opt_src[0]; v[1] = opt_src[1]; v[2] = opt_src[2];
  }
  this.elements = v;
}

/**
 * Normalize.
 * @return this
 */
Vector3.prototype.normalize = function () {
  var v = this.elements;
  var c = v[0], d = v[1], e = v[2], g = Math.sqrt(c * c + d * d + e * e);
  if (g) {
    if (g == 1)
      return this;
  } else {
    v[0] = 0; v[1] = 0; v[2] = 0;
    return this;
  }
  g = 1 / g;
  v[0] = c * g; v[1] = d * g; v[2] = e * g;
  return this;
};

/**
 * Constructor of Vector4
 * If opt_src is specified, new vector is initialized by opt_src.
 * @param opt_src source vector(option)
 */
var Vector4 = function (opt_src) {
  var v = new Float32Array(4);
  if (opt_src && typeof opt_src === 'object') {
    v[0] = opt_src[0]; v[1] = opt_src[1]; v[2] = opt_src[2]; v[3] = opt_src[3];
  }
  this.elements = v;
}

export default Matrix4;
